HHVM-52: Added test cases for serialization from spec
HHVM-52: Added test cases for serialization from spec

mongodb-labs/mongo-hhvm-driver-prototype,bjori/mongo-hhvm-driver-prototype,10gen-labs/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver,10gen-labs/mongo-hhvm-driver-prototype,10gen-labs/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver,jmikola/mongo-hhvm-driver,jmikola/mongo-hhvm-driver,bjori/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver-prototype,mongodb/mongo-hhvm-driver,jmikola/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver,10gen-labs/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver,jmikola/mongo-hhvm-driver-prototype,mongodb/mongo-hhvm-driver,mongodb/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-prototype,bjori/mongo-hhvm-driver-prototype,bjori/mongo-hhvm-driver-prototype,mongodb/mongo-hhvm-driver